M.S.
I have 19 month old twin boys and I STILL put them to sleep with a bottle. there's nothing wrong with bottles to go to bed, it's comforting. Give them back their bottles and all of you get some sleep. You'll know when it's time to stop giving the bottles, it'll be when they can actually reason. All they know now is that you took away something they need and they don't know why nor can they understand why. Good luck